Conventionally, a heat exchanger is known, in which flow passage pipes hold both sides of a heating element to dissipate a heat of the heating element such as a semiconductor module including a semiconductor element. In such heat exchanger, the heating elements and the flow passage pipes are stacked alternately with each other, and multiple flow passage pipes are communicated with each other by communication members such that a cooling medium flows in each of the flow passage pipes.
In order to improve a thermal performance of heat exchange of such heat exchanger, a configuration is disclosed, in which a partitioning member is provided in the flow passage pipe to partition one flow passage pipe in a thickness direction of the flow passage pipe into two heat medium passages. An inner fin is provided in each of the two heat medium passages.
In a heat exchanger disclosed in Patent Document 1, a wavy fin is used for increasing an area for heat transfer, for example.